1. Field of the Invention
The present invention relates to a device including a contact structure and a method of forming the same.
2. Description of the Related Art
Contact structures may be employed in a number of devices, e.g., semiconductor devices, optoelectronic devices, etc., where it is desired to electrically connect a lower conductive pattern to an upper conductive pattern. A contact structure may be, e.g., a contact pattern such as a plug that is formed in a via or hole passing through a layer that separates the upper and lower conductive patterns. For example, the contact structure may be a contact plug that penetrates an insulating layer interposed between the lower conductive pattern and the upper conductive pattern. A lower end and an upper end of the contact plug may be connected to the lower and upper conductive patterns, respectively, in order to electrically connect the lower and upper conductive patterns.
In order to increase the degree of integration of a device including the contact structure, it may be desirable to reduce the size of the contact structure. For example, where the contact structure is a contact plug having a generally cylindrical shape, it may be desirable to reduce the diameter of the contact plug. However, reducing the size of the contact structure may impact the ability of the structure to carry an electrical current. Moreover, if the amount of current flowing through the contact structure decreases, characteristics of the device may be degraded. For example, if the current is not sufficiently supplied or discharged, a signal delay or the like may occur, which may generate an operational error in the device. This may make it difficult to reduce the size of the contact structure, may lower an operation speed of the device, etc.
One approach to reducing the size of the contact structure is to form a contact plug of a metal-containing material, e.g., copper, titanium nitride, etc. For example, copper may support a current flow per unit area, i.e., a current density, of up to about 107 A/cm2. Similarly, titanium nitride may support a current density of up to about 108 A/cm2. However, a contact plug formed of copper or titanium nitride may still require a diameter of the contact plug of 50 nm or more. That is, if the diameter of the contact plug is smaller than about 50 nm, the characteristics of the device may be degraded. Accordingly, there is a need for a device suitable for a high degree of integration and/or high-speed operation, and a method of forming the same.